Multi-carrier transmission/reception apparatus

Abstract

A multicarrier radio communication technology that enables radio resources to be used effectively, interference-to be suppressed, and a cell search to be performed at high speed, in a multicarrier CDMA system. In this technology, a secondary synchronization code (S-SCH signal) for identifying the group of scrambling codes divided into groups beforehand is frequency multiplexed in a plurality of subcarriers. A secondary synchronization code is coded in the time direction. Subcarriers in which a secondary synchronization code is multiplexed are mutually separated and equally spaced. The number of subcarriers in which a secondary synchronization code is multiplexed can be set to a small value with respect to the total number of subcarriers. A secondary synchronization code is an orthogonal code. On the receiving side, a cell search is carried out using such a frequency multiplexed type S-SCH.

1. A multicarrier transmitting apparatus that performs radio communication by combining a multicarrier modulation method with a code division multiple access method, the multicarrier transmitting apparatus comprising:
 a multicarrier signal forming section that forms a multicarrier signal including a pilot signal and a scrambling code group identification code for identifying a group of scrambling codes divided into groups beforehand; and 
 a transmission section that transmits the multicarrier-signal formed in the multicarrier signal forming section, wherein: 
 in the multicarrier signal formed in the multicarrier signal forming section, the pilot signal is mapped in a frequency direction at predetermined time intervals and the scrambling code group identification code having a shorter time length than the predetermined time intervals is mapped in a time direction, such that an overlapping proportion of the pilot signal and the scrambling code group identification code is minimized. 
 
   
   
     2. The multicarrier transmitting apparatus according to  claim 1 , wherein a time slot defines the predetermined time intervals for mapping the pilot signal. 
   
   
     3. The multicarrier transmitting apparatus according to  claim 1 , wherein the scrambling code group identification code is placed in a plurality of frequencies. 
   
   
     4. The multicarrier transmitting apparatus according to  claim 3 , wherein the plurality of frequencies are mutually separated frequencies. 
   
   
     5. The multicarrier transmitting apparatus according to  claim 1 , wherein the scrambling code group identification code is an orthogonal code. 
   
   
     6. A base station apparatus comprising the multicarrier transmitting apparatus according to  claim 1 . 
   
   
     7. A multicarrier receiving apparatus that performs radio communication by combining a multicarrier modulation method with a code division multiple access method, the multicarrier receiving apparatus comprising:
 a reception section that receives a multicarrier signal including a pilot signal and a scrambling code group identification code for identifying a group of scrambling codes divided into groups beforehand; 
 an extraction section that extracts the scrambling code group identification code from the multicarrier signal received by the reception section; 
 a first identification section that identifies a scrambling code group using the scrambling code group identification code extracted by the extraction section; and 
 a second identification section that identifies a scrambling code used by the received multicarrier signal based on the scrambling code group identified by the first identification section, wherein: 
 in the multicarrier signal received by the reception section, the pilot signal is mapped in a frequency direction at predetermined time intervals and the scrambling code group identification code having a shorter time length than the predetermined time intervals is mapped in a time direction, such that an overlapping proportion of the pilot signal and the scrambling code group identification code is minimized. 
 
   
   
     8. A base station apparatus comprising the multicarrier receiving apparatus according to  claim 7 . 
   
   
     9. A multicarrier radio communication method in a multicarrier transmitting apparatus that performs radio communication by combining a multicarrier modulation method with a Code Division Multiple Access method, the multicarrier radio communication method comprising:
 a multicarrier signal forming step of forming a multicarrier signal including a pilot signal and a scrambling code group identification code for identifying a group of scrambling codes divided into groups beforehand; and 
 a transmission step of transmitting the formed multicarrier signal, wherein: 
 in the multicarrier signal formed in the multicarrier signal forming step, the pilot signal is mapped in a frequency direction at predetermined time intervals and the scrambling code group identification code having a shorter time length than the predetermined time intervals is mapped in a time direction, such that an overlapping proportion of the pilot signal and the scrambling code group identification code is minimized. 
 
   
   
     10. A multicarrier radio communication method in a multicarrier receiving apparatus that performs radio communication by combining a multicarrier modulation method with a Code Division Multiple Access method, the multicarrier radio communication method comprising:
 a reception step of receiving a multicarrier signal including a pilot signal and a scrambling code group identification code for identifying a group of scrambling codes divided into groups beforehand; 
 an extraction step of extracting the scrambling code group identification code from the multicarrier signal received in the reception step; 
 a first identification step of identifying a scrambling code group using the scrambling code group identification code extracted in the extraction step; and 
 a second identification step of identifying a scrambling code used by the received multicamer signal based on the scrambling code group identified in the first identification step, wherein: 
 in the multicamer signal received in the reception step, the pilot signal is mapped in a frequency direction at predetermined time intervals and the scrambling code group identification code having a shorter time length than the predetermined time intervals is mapped in a time direction, such that an overlapping proportion of the pilot signal and the scrambling code group identification code is minimized.